Alkanoyl esters of the trihydroxy benzenes



Aug. l5, 1967 w. H. voRls ALKANOYL 'ESTERS OF THE TRIHYDROXY BENZENES Filed sept. 17, 1964 savais/maa 'umass/A suvwaN/,v l

United States Patent O 3,335,349 Patented Aug. 15, 1967 rice 3,336,349 carboxyl group of the neo acid structure. The esters can ALKANOYL ESTERS F THE TRlHYDROXY be represented as BENZENES O A, William H. Voris, Mars, Pa., assignor to Koppers Company, Inc., a corporation of Delaware 5 Filed Sept. 17, 1964, Ser. No. 397,154 A1'0 O-A2 13 Claims. (Cl. 260-410.5)

where A1 is an acyl group containing 6-20 carbon atoms ABSTRACT 0F THE DISCLQSURE and A2 is an acyl group containing 2-20 carbon atoms. Synthetic lubricants are provided which have excep- Tltle estlcatigndcan bei) convemenily Gamed out by tionally wide viscosity ranges, unusually good viscositygrlige e m y roxy enzene Wlth any alkanoyl temperature relationships and a high degree of thermal a-nd oxidative stability. The synthetic lubricants consist of The Invention WIH be Illustrated further by the follow' mg examples. alkanoyl esters of the trihydroxy benzenes. The lubricants 15 EXAMPLE I are especially useful for modern jet engines.

There was added 16 grams of dehydrated phloroglucinol (0.127 mole), l5() milliliters of toluene, and 2 milliliters This invention relates generally to synthetic lubricants of dmothylfofmamide to a 500 milliliter llaSk equipped and more particularly to the use of the alkanoyl esters of 20 With a Dean-Stark trap. trihydric phenols. The mixture was heated to 90 C. and n-heptanoyl Petroleum based lubricants have worked well for pis- Chloride (625 g 0-42 molo) (10% eXCeSS) then added ton-type engines. Modern jet engines demand the lubrithrough a dropping funnel over a Period of about thirty cants to withstand such severe conditions of temperature, minutes while the temperature was maintained between oxidation, load pressure, and radiation exposure that the 102-110o C. Hydrogen chloride evolved vigorously from petroleum lubricants cannot meet the requirements. Atthe reaction mixture as the Orange Solids Went into tempts are being made, therefore, to develop synthetic solution. Heating of the reaction to a temperature of lubricants that will qualify. 103-106 C. was continued for six hours during which It has now been .found that the alkanoyl esters of tritime 'the HC1 eVolution finally ceased. The mass was hydroxy benzene provide superior lubricants. Such esters l cooled to about room temperature and pyridine (20 ml.) have exceptionally wide viscosity ranges, unusually good was then added. The mass was again heated to 100 C. viscosity-temperature relationships, and a high degree of and there maintained for another two hours. thermal and oxidative stability. The crude product was washed successively with dilute The trihydroxy benzenes, pyrogallol (1,2,3-trihydroxy hydrochloric acid, then with dilute caustic, and therebenzene), phloroglucinol (1,3,5-trihydroxy benzene), and after with water until the nal wash was neutral. hydroxy hydroquinone (1,2,4-trihydroxy benzene), are The toluene was removed from the reaction mass by well known for specialty uses. Pyrogallol (1,2,3etrihy- Vacuum distillation and the residue, a clear red liquid, dr-oxy benzene), for example, is an important -photo- 49 g. or 83.5% of theory remained. graphic developer. Phloroglucinol (1,3,5-trihydroxy ben- Distilling the product to a residue temperature of zene) is a useful reagent for analytical purposes, for ex- 230 C. at the subatmospheric pressure of 0.5 mm. H ample, for the estimation of furfural. yielded only 0.3 g. colorless distillate while the color of The preferred esters usable in accordance with this inthe product reside turned from red to dark brown. The vention are those formed from the trihydroxy benzene product contained no free hydroxyls (LR.) showed a and alkanoyl radicals having from six to twenty carbon trace amount of a carbonyl impurity (by 1.11.), gave an atoms. It is possible, however, to use as a lubricant those acid No. of 0.1 mg. KOH/g. and a saponication No. esters wherein two of the three acyl groups contain from of 455 mg. KOH/ g. (theory=728), the saponication No. two to twenty carbon atoms. It is preferred to use the neo showing less than 63% decomposition. acids for the esteriiication because the neo acid (2,2-di- The general characteristics are illustrated also in the alkylacyl) esters of the trihydric phenols have good staattached drawing. The compounds listed on the drawing bility against oxidation and thermal decomposition. This were also prepared following the above general procedure. characteristic is believed to be due to the absence of The general characteristics of these compounds are also tertiary hydrogen atom on the carbon atom alpha to the illustrated in Table l.

TABLE 1 Thermal Stability Viscosity, est. 13,000 500,000 Pour Tests,'1GA (in air) Ester ASTM Viscosity est. T, est. T, Point, F.

Slope Index F. F.

F. 210 F. 275 F. T 10% T 10% Phloroglucinol Triheptanoate 35 6. 4 0. 66 139 -40 +79 -53 549 620 Pyrogallol Triheptanoate 29 5.1 0.73 116 -35 -70 -4 518 586 Phloroglucinol Triueoheptanoate 2, 210 71 0. 64 89 +66 +15 +32 545 662 Pyrogallol Trineoheptanoate 138 10 0. 80 34 +17 -18 0 404 532 Hydroxyhydrooninone Trineoheptanoate 205 14 0. 74 60 +23 -17 0 505 56S Phloroglneinol Trilaurate 186 15 7 0` 70 86 (l) 572 715 Phloroglucinol Trineotrideeanoate 28,000 163 35 0.76 (2) +112 +65 572 700 1 Sets up as a grease at room temperature.

2 Viscosity level above range used for V.I. calculation;

"D .D EXAMPLE II Pyrogallol acetate-hexmzolate-neolzeptancate Pyrogallol (126 g., 1.0 mole) .and toluene (1500 ml.) were charged to a liask equipped with a Dean-Stark trap, reux condenser, thermometer, and stirrer. The mixture was stirred and heated to reliux. A small amount of water was removed by azeotroping distillation by draining of the Dean-Stark trap until 100 ml. toluene had been removed and the trap contents were no longer cloudy. The mixture was cooled to 70 C. Then acetyl chloride (78.5 g., 1.0 mole) was added over a period of 20 minutes while the reaction mass was being stirred and maintained at a temperature of 70-90 C. The heating of the mass was continued for about 2 hours until no more hydrogen chloride evolution was observed and the mixture was reiluxing at about 110 C. The mixture was cooled to 70 C. Then, n-hexanoyl (caproyl) chloride (135 g., 1.0 mole) was added over a period of 20 minutes while the reaction mass was stirred and maintained at a temperature of 80-90 C. Thereafter heating was continued for about -2 hours until there was no more evidence of hydrogen chloride evolution and the mixture was reuxing at 110 C. The reaction mass was again cooled to 70 C. and neoheptanoyl chloride (164 g., 1.1 mole) added over a period of 20 minutes while stirring the reaction mass and maintaining the temperature of their reaction mass at 85-90 C. Thereafter heating was continued for about 2 hours until there was little evidence of hydrogen chloride evolution and the solution was refluxing at about 110 C. After cooling the reaction mass to 40 C., pyridine (S0 ml.) was added. Again the mixture then heated to 110 C. and maintained at this temperature for 2 hours to assure completeness of the esteriication. The reaction mass was then cooled, washed successively with a dilute solution of hydrochloric acid, a dilute solution of sodium hydroxide, and nally with distilled water until the wash water was neutral to pH indicator paper. Toluene was removed from the reaction mass by distillation. Then the distillation was continued under vacuum until the temperature of the residue reached 200 C. at the subatmospheric pressure 0.5-1.0 mm. Hg. Only a few milliliters of distillate was collected. The monoacetate-monohexanoate-mononeoheptanoate of pyrogallol obtained as the residue (340 g., 90% yield) was an amber colored oil containing no free hydroxyls (by infrared analysis), and had an acid No. of 0.2 mg. KOH per gram. Other characteristics were:

Viscosity at 100 F cs 99 Viscosity at 210 F. cs 9.45 ASTM slope 0.76 Pour point F -30 13,000 cs. temp. F -|-5 EXAMPLE III Hydroxyhydroquinone (126 grams 1.0 mole) and toluene (1500 milliliters) were charged to a ask equipped with a Dean-Stark trap, reflux condenser, thermometer, and stirrer. To dehydrate the material, the mixture was stirred and heated to reux and any water was removed by azeotropic distillation by draining the Dean- Stark trap until 100 milliliters toluene had been removed and the trap contents were clear. The mixture was cooled to 70 C. and neotridecanoyl chloride (232 grams, 1.0 mole) was added over a period of twenty minutes while the reaction mass was being stirred and maintained at a temperature of 70-90 C. Heating of the mass was continued for about two hours until no more hydrogen chloride evolution was observed and the mixture was reuxed at about 110 C. The mixture was cooled to 70 C. then eicosanoyl chloride (331 grams, 1.0 mole) was added over a period of thirty minutes while the reaction mass was being stirred and maintained at a temperature of 80- 90 C. Thereafter, heating was continued again for about two hours until there was no more evidence of hydrogen chloride evolution and the mixture was refluxing at about 110 C. The reaction mass was again cooled to 70 C. and acetyl chloride (86.4 grains, 1.1 mole) was added over a period of 20 minutes while stirring the reaction mass and maintaining the temperature of the of the reaction mass at 90 C. Heating was continued for about two hours until no further evolution of hydrogen chloride was observed and the solution was reuxing at about 110 C. After cooling the reaction mass to 40 C. pyridine (80 milliliters) was added. Again the mixture was heated to reux at about 110 C. and maintained at this temperature for two hours to assure completeness of esterication. The reaction mass was then cooled, and washed successively with dilute hydrochloride solution, with dilute sodium hydroxide solution, and finally with distilled water until the wash water was neutral to pH indicator paper. Toluene was removed from the reaction mass by distillation. Then the distillation was continued under vacuum until the residue reached a temperature of 200 C. at the subatmospheric pressure of 0.5-1.0 millimeters of mercury.

The yacetate-eicosanoate-neotridecanoate of hydroxyhyvdroquinone which remained as the residue (460 g., 70% yield) was a dark colored oil containing no free hydroxyl groups (by infrared analysis) and had an acid No. of 1.0 mg. KOH/g. It also had:

Viscosity at F. cs 30,000 Viscosity `at 210 F. cs 175 ASTM slope cs 0.76 Pour Point F 70 EXAMPLE IV The general procedure of Example III was repeated except that (a) 1 mole of phloroglucinol was substituted for a mole of hydroxyhydroquinone, (b) lauroyl chloride (219 grams, 1.0 mol) was substituted for the neotridecanoyl chloride and (c) n-butanoyl chloride (107 grams, 1.0 mole) was substituted for the eicosanoyl chloride of Example III.

The acetate-butyrate-laurate of phloroglucinol obtained as the residue (337 grams, 80%) was a straw colored oil containing no free hydroxyl groups (by LR.) and had an r acid No. of 0.4 mg. KOH/g. It also had:

Viscosity at 100 F cs 30 Viscosity at 210 F. cs 5.74 ASTM slope 0.68 Pour point F -75 13,000 cs. temp. F -45 EXAMPLE V Phloroglucinol (126 grams, 1.0 mole) and toluene (1500 milliliters) were charged to a ask equipped with a Dean-Stark trap, reux condenser, thermometer and stirrer. The material was dehydrated by heating the mixture to reux so that any water was removed by azeotropic distillation by draining the Dean-Stark trap until 100 milliliters toluene had been removed and the trap contents were clear. The mixture was cooled to 70 C. A mixture consisting of lauroyl chloride (219 grams, 1.0 mole), n-butanoyl chloride (107 grams, 1.0 mole) and acetyl chloride (86.4 grams, 1.1 mole) was added over a period of ninety minutes while the reaction mass was stirred and maintained at a temperature of 70-90 C. Heating was continued for six hours until no more hydrogen chloride evolution was observed and the solution was reuxing at 110 C. The solution was cooled to 40 C. and pyridine (80 ml.) was added. Heating was resumed and the temperature of the reaction mass was maintained at reux at about 110 C. for about two hours. The reaction mass was cooled, washed successively with a dilute solution of hydrochloric acid, a dilute solution of sodium Viscosity at 100 F. cs 20 Viscosity at 210 F. cs 4.37

ASTM slope 0.70

Pour point F-- -80 13,000 cs. temp. F 55 EXAMPLE VI Phloroglucinol (126 grams, 1.0 mole) and toluene (1500 milliliters) were charged to a ask equipped with a Dean-Stark trap reux condenser, thermometer and stirrer. The mixture was dehydrated by being stirred and heated to reux and any Water coming oif by azeotropic distillation was removed by draining the Dean-Stark trap until 100 milliliters of toluene had been removed and the trap contents were clear. The mixture was cooled at 70 C.; then cyclohexane carbonyl chloride (485 grams, 3.3 mole) was added over a period of ninety minutes while the reaction mass was being stirred and maintained at a temperature of 80-90 C. Heating was continued for six hours until no evolution of hydrogen chloride was observed and the solution was reiluxing at about 110 C.

The solution was cooled to about 30 C. and 80 milli' liters of pyridine was added. The reaction mass was then again heated to 110 C. and the temperature then maintained at reux for another two hours to assure completeness of the esterication. The reaction mas was cooled, washed successfully with dilute solutions of hydrogen chloride and of sodium hydroxide and, finally, with distilled Water until the wash water was neutral to pH indicator paper. The toluene was removed from the reaction mass by distillation. Then the distillation was continued under vacuum until the temperature of the residue reached a temperature of 200 C. at the subatmospheric pressure of 0.5 to 1.0 millimeter of mercury.

The phloroglucinol tricyclohexanecarboxylate obtained as the residue (321 g. 70% yield) was a brownish colored oil containing no free hydroxy groups (by LR. examination) and had an acid No.- of 0.1 mg. KOH/g. It also had:

Viscosity at 100 F cs 2100 Viscosity at 210 F. cs 75 ASTM slope 0.63

Pour point F-- EXAMPLE vn `83% yield) was a clear brown oil containing no free hydroxyl groups (by infrared analysis) which had an acid No. of less than 0.1 mg. KOH/ g. It also had:

Viscosity at 100 F. cs 75 Viscosity at 210 F cs 9.28 ASTM slope v 0.70 Pour point F-- -50 13,000 cs. temp. F-- -10 EXAMPLE vm The general procedure of Example III was followed except that there Was substituted (a) cyclohexanecarbonyl chloride (147 grams, 1.0 mole) for the neotridecanoyl chloride of Example III, (b) neoheptanoyl chloride (149 grams, 1.0 mole) for the eiscosanoyl chloride of Example III, and (c) propionyl chloride (102 grams, 1.1 mole) for the acetyl chloride of Example III.

The propionate-neoheptanoate-cyclohexanecarboxylate of hydroxyhydroquinone obtained as the residue was a yellow oil containing no free hydroxyl groups (by I.R. analysis) and had an acid No. of 0.2 mg. KOH/ g. It also had:

Viscosity at F 30.7 Viscosity at 210 F 4.45 ASTM slope 0.83 Pour point F -40 13,000 cs. temp. F -20 EXAMPLE IX The hydrolytic stabilities of these esters were measured by a severe saponication test under which conditions di(2ethylhexyl) sebacate and di(isooctyl)azelate, components of some commercial synthetic lubricants, are completely hydrolyzed. The data in the table below illustrate the superior hydrolytic stabilities which the trialkanoates of the trihydroxybenzenes have over the standard aliphatic dibasic acid esters.

Sap. N o. (mg. KOH/g.) Percent Ester Hydrolysis Found Theory Phloroglucinol tri-mheptanoate 455 728 62 Pyrogallol tri-n-heptanoate 650 728 89 Pyrogallol trineoheptano ate 463 728 63 Hydroxyhydroquinone tr i n e o h e p t anoate 597 728 82 Saponication number (found) Percent hydm1ys1s=100 Saponifcation number (theoretical) EXAMPLE X Wear characteristic tests of the esters of trihydroxybenzenes were conducted in the Shell four-ball wear tester. Test conditions were: Testtime of l hour; test temperature at 167 F.; test speed at 620 r.p.m. and bearings of 52-100 steel. The results are illustrated below:

l A standard ester lubricant.

I 1. Phloroglucinol triheptanoate.

2. Phloroglucinol trilaurate.

3. Phloroglucinol trineoheptanoate. 4. Phloroglucinol trineotridecanoate. 5. Pyrogallol triheptanoate.

6. Pyrogallol trineoheptanoate.

7 8 7, Hydroxyhydroqunone trineoheptanoate. 13. Propionate neoheptanoate-cyclohexanecarboxylate 8. Pyrogallol acetate-hexanoate-neoheptanoate. of hydroxyhydroquinone. 9. Acetate-eicosanoate-neotridecanoate of hydroxyhydr0quin0ne References Cited 10- Acetate-butyrate-laufate 0f PhlOrOgluCinOL 5 David et a1.: Bun. soc. Chim. France (1953) v01. 20, 11, Phloroglucinol tricyclohexanecarboxylate. pp 183 g4 12. Propionate 2 ethylbutanoate-Z-ethylhexanoate of hydroxyhydroquinone. HENRY R. J ILES, Primary Examiner. 

1. PHLOROGLUCINOL TRIHEPTANOATE.
 2. PHLOROGLUCINOL TRILAURATE.
 11. PHLOROGLUCINOL TRICYCLOHEXANECARBOXYLATE. 